1. Field of the Invention
The present invention relates to an operating microscope provided with at least one motor for a magnification adjustment (zoom), a distance or focus adjustment (focus), an X adjustment or canting, and a Y adjustment or tilt.
2. Description of the Related Art
In operating microscopes, following a adjustment of the tilt or canting, a correction or the focus has to be carried out in each case when the imaging object represents a surface. For microscopic viewing of different areas of a stereoscopic surface, the tilt, canting and focus will likewise have to is adjusted in order that a sharply defined image be obtained.
In order to facilitate a respective readjustment of the focal length, the canting, and the tilt of the microscope, the microscopes known in the state of the art are provided with appropriate motors or gearings. On the one hand, this has the advantage that the microscopes may also be positioned outside the work area of the operating surgeon, as on the ceiling or on a wall where they do not impede the operation to be viewed. The adjustment with the aid of servomotors does, as a rule, also requires less time and can be effected with greater accuracy. However, these adjustments also call for precise work by the microscope operator which, with a single gear stage, requires a great sensitivity. When a fine adjustment exists, a costly further gear stage is needed.
A further substantial disadvantage of existing operating microscopes is caused by the fact that operating surgeons often compelled to adapt the motor speeds manually in accordance with the respective adjusting conditions as to be able to readjust in an optimal manner. Since the selected magnification of the microscope determines the resolution and the depth of focus of the apparatus, a greater need for exact focussing exists in the smaller depth of focus ranges (higher magnifications). As a rule, this can be achieved only be carrying out the focussing at lower speeds at higher magnifications, while a higher focussing speed may be selected at lower magnification.
The selected measure of magnification determines the imaged object space so that, at a uniform given speed of adjustment, the optical image adjustment of the X motion and/or the Y motion at higher magnifications, is relatively slow and , conversely, in lower magnifications, takes place very slowly. In microscopes that have only a uniform X and/or Y adjusting speed makes finding the desired operating field more difficult. Thus, as is the case with the focussing speed, the X and Y adjusting speeds are preferably relatively high at low magnification and relatively low at high magnification.